1. Field of the Invention
The invention relates to a projection display apparatus.
2. Description of the Related Art
FIG. 1 is a schematic view of a conventional projection display apparatus disclosed in U.S. Pat. No. 6,943,850 ‘OPTICAL APPARATUS AND PROJECTION TYPE DISPLAY APPARATUS FOR REDUCING A PHYSICAL DISTANCE BETWEEN A LIGHT SOURCE AND A DISPLAY’. The conventional projection display apparatus 10 comprises a light source 11, a pair of lens arrays 12 and 13, a quarter wave plate 14, a mirror 15, two prisms 16 and 19, two lenses 17 and 18, a light valve module 20 and a projection lens 21. In the conventional projection display apparatus 10, an illumination beam emitted from the light source 11 passes through the lens arrays 12 and 13 and the lens 17, and then enters the prism 16. Next, the illumination beam passes through the prism 16, enters the quarter wave plate 14, and then is reflected by the mirror 15. Following, the illumination beam enters the prism 16 again and is perpendicularly reflected into the lens 18 and the prism 19. Next, the illumination beam is perpendicularly refracted into the light valve module 20 via the prism 19 and returns the prism 19. Finally, the illumination beam enters the projection lens 21. The conventional projection display apparatus 10 has a pair of lens arrays 12 and 13. Thus, distance between the lens arrays 12 and 13 increases the volume of the projector. Light and thin electronic devices bring convenience, thus, miniaturization of electronic devices is important for a manufacturer.